1. Field of the Invention
The present invention relates to a transmission for an internal combustion engine.
2. Description of Background Art
A known transmission for an internal combustion engine performs gearshifting by using a gear that fits over splines on a shaft and is thereby axially moved to be engaged with, or disengaged from, an adjacent gear by a dog disposed on one side and a dog hole disposed on the other side. See, for example, Japanese Patent Laid-open No. 2009-83684.
Because of play between the gear and the splines in the transmission for an internal combustion engine disclosed in Japanese Patent Laid-open No. 2009-83684, a contact surface of the dog tilts when the dog fits into (is connected with) the dog hole, so that a thrust force is produced in a direction of disengaging a dog clutch. As a result, a friction force produced in a contact surface between a shift fork that axially moves the gear and the gear becomes large, so that the shift fork wears a large amount. To prevent this from occurring, it becomes necessary either to make a fit length longer between the dog and the dog hole or to extend the splines of the gear. This, however, result in the transmission having a longer axial length.